import type { Database } from 'bun:sqlite';
import { db } from '../db';

type CreateTaskInput = {
  description: string;
  due_date?: string | null; // Expect 'YYYY-MM-DD' or null
  group_id?: string | null; // Full JID (e.g., 'xxx@g.us') or null
  created_by: string;       // Normalized user ID
};

type CreateAssignmentInput = {
  user_id: string;    // Normalized user ID
  assigned_by: string; // Normalized user ID (typically created_by)
};

export class TaskService {
  static dbInstance: Database = db;

  static createTask(task: CreateTaskInput, assignments: CreateAssignmentInput[] = []): number {
    const runTx = this.dbInstance.transaction(() => {
      const insertTask = this.dbInstance.prepare(`
        INSERT INTO tasks (description, due_date, group_id, created_by)
        VALUES (?, ?, ?, ?)
      `);

      const runResult = insertTask.run(
        task.description,
        task.due_date ?? null,
        task.group_id ?? null,
        task.created_by
      );
      const taskId = Number((runResult as any).lastInsertRowid);

      if (assignments.length > 0) {
        const insertAssignment = this.dbInstance.prepare(`
          INSERT INTO task_assignments (task_id, user_id, assigned_by)
          VALUES (?, ?, ?)
        `);

        // Evitar duplicados por (task_id, user_id)
        const seen = new Set<string>();
        for (const a of assignments) {
          if (seen.has(a.user_id)) continue;
          seen.add(a.user_id);
          insertAssignment.run(taskId, a.user_id, a.assigned_by);
        }
      }

      return taskId;
    });

    return runTx();
  }

  // We'll add more methods here as we progress
}